In rehabilitation robotic, orthotic, or prosthetic applications, devices have been used to apply forces including torques to various points on the human body in order to manipulate those points. When such devices apply forces or torques under programmable computer control, it is said that the human body is subject to robotic manipulation.
Current robotic manipulation can be used to provide benefits to clinicians and patients that include, but are not limited to, assessment, motor control studies, and therapy of both healthy people and people with neuromuscular difficulties. However, the robotic machines developed to date have been limited for use in a laboratory setting.
A robotic machine capable of training or rehabilitating its human user at home or otherwise outside of a laboratory has the potential to be used more often and thus be more effective. Such a robotic machine should be lightweight, inexpensive, and portable, which current rehabilitation robotic machines cannot offer.
Rehabilitation robotic devices known as the STRING-MAN device (Surdilovic et al. “STRING-MAN: A New Wire Robotic System For Gait Rehabilitation”, Proc. 8th International Conference on Rehabilitation Robotics, 2003) and MACARM device (Mayhew et al. “Development of the MACARM—a Novel Cable Robot for Upper Limb Neurorehabilitation”. Proceedings of the 2005 IEEE, 9th International Conference on Rehabilitation Robotics, Chicago, Ill. 2005) use cables to actuate a human user's joints. The torque on the human user's joint is controlled by changing the tension in the wires.
The MIT Manus device uses a five-bar linkage and two torque motors to produce a planar haptic interface (Hogan et al. “MIT-MANUS: a workstation for manual therapy and training”, IEEE International Workshop on Robot and Human Communication”, pp. 161-165, Tokyo, Japan 1992). As a linkage, where the individual bars are of fixed length, motion pathways are prescribed by the motions of the joints and by design and size of the linkage.
Several human interactive robots have embodied Bowden cables guided by pulleys or drums. For example, such a robot is described by Jacobsen et al. in “Design of the Utah/MIT Dextrous Hand”, Proc. IEEE International Conference on Robotics and Automation (ICRA), San Francisco 1986. Also see Salisbury et al. “The Design and Control of an Experimental Whole-Arm Manipulator”, Proc. 5th Int. Symp On Robotics Research 1989; and Perry et al. “Design of a 7-Degree-of-Freedom Upper-Limb Powered Exoskeleton”, Proc. Int. Conf. of Biomedical Robotics and Biomechatronics, Pisa, Italy 2006.
A robotic actuator for dynamic legged locomotion using a cable-driven series elastic actuator is described by Hurst et al. in “An Actuator with Physically Variable Stiffness for Highly Dynamic Legged Locomotion”, International Conference on Robotics and Automation, New Orleans 2004). Also see Veneman et al. “Design of a Series Elastic and Bowden cable-based actuation system for use as torque-actuator in exoskeleton-type training”, International Conference on Rehabilitation Robotics, Chicago, Ill. 2005).
A robotic machine that embodies two elastic bands connected to a passive (non-driven) circular disk and that relies on torque unbalance to cause the passive disk to jump between positions is described by Zeeman in “Catastrophe Theory: Selected Papers”, Addison-Wesley 1972-1977.